Roxanna and John Green, who lost their 9-year-old daughter in the Tucson shootings, say they have found some solace in the news this week that Christina-Taylor's organs have saved the life of a little girl in Boston and brought sight to two other children in Arizona.

"It was a blessing when we heard about the children," Roxanna Green told ABCNews.com. "It gives us some comfort that Christina would have wanted this. She was a giver. She was very strong…We didn't think twice about this. We are so honored we could help these children."

She said the family was committed to organ donation and urged others to consider that option after the tragic death of a child. "Take the time and think about this," she said.

"I knew we would need to talk about it as soon as we paid respects to Christina and prayed for her and she was up in heaven with God," said Roxanna Green, a devout Catholic. "She wanted to help others. That's what she wanted to do in life."

The couple learned Monday that their daughter's corneas had saved the eyesight of two children. Christina was the youngest victim of the shooting that left a total of six dead and 13 others wounded, including Rep. Gabrielle Giffords.

"We grew up in this family that believes in helping others, and it's the right thing to do," said Roxanna Green. "In this tragedy I lost my daughter and it was horrible and she is never going to come back, so why not help someone else, to help them live a better life with their sight or organs? It's a fair thing to do."

"This is a really beautiful story," said ABC's Dr. Richard Besser. "How one family in the midst dealing with their own incredible tragedy, reaches out to help another, to bring them something that is so important."

Because not many children die and there is a lack of awareness about organ donation, more than 1,900 children under the age of 18 still sit on the national waiting list, according to Besser.

"It's important to have this conversation," he said. "It can bring meaning and comfort at a time of incredible loss."

John Green, a scout for the Los Angeles Dodgers, said he feared that their daughter's organs would be unusable because of the severity of the gunshot wounds.

"The fact that her organs were able to help people, that was an amazing thing to me," he told the Associated Press. "It's just another thing that this little girl has given the world."

The Greens moved to Tucson specifically so Roxanna could care for her aging mother, according to the Los Angeles Times.

The family has suffered two losses in the last year -- their daughter and Roxanna Green's mother, who died of a brain-bleeding incident at the age of 74, but was otherwise healthy.

"We donated my mother's organs and Christina thought that was fabulous," said her mother.

Roxanna Green said she had no idea the specifics of Christina-Taylor's donations, because the family could not keep up with the phone calls since the Jan. 8 shooting incident.

"Our phone has been ringing 24/7 and we have been waiting to hear," she said.

The recipients of the 9-year-old's organs are also anonymous, unless they decide to speak out.

Christina-Taylor Green Family Urges Organ Donation

The family has been a big supporter of the organ donation program.

"They approach you at a time after you have received the tragic news and it has to be done in a timely manner," she said. "It was always something I knew we were going to do and I know it has to be done immediately. Had they not asked, we would have offered."

The United Network for Organ Sharing, the nonprofit group that allocates organs once they are recovered and matches them with recipients, has said in a prepared statement that the family of Christina-Taylor has set a positive example for others.

"We are grateful for everyone who chooses to save and enhance the lives of others through organ, eye and tissue donation," said Charles Alexander, UNOS president and CEO of The Living Legacy Foundation of Maryland. "We hope their example inspires others to respond by making a commitment to donate."

An estimated 110,000 Americans are on a waiting list for an organ transplant. Of those, 90 are under the age of 1; 1,528 are aged 1 to 5; 350 are aged 6 to 10; and 785 are 11 to 17, according to UNOS.

In 2009, the last year for which there is data, 28,463 transplants were performed. Of those, 331 were for children under the age of 1; 592 for children 1 to 5; 315 for those 6 to 10; and 780 for children 11 to 17.

One donor can help up to eight people with various organs. The greatest need for all age groups are donated kidneys, followed by the liver. Adults can also donate a part of those organs to children.

Of the estimated 8,000 deceased organ donors last year about 800 were children, according to UNOS.

The decision a parent must make can be guided by their knowledge of the child.

"A lot of times an older kid who has learned about organ donation in school and has told his parents, makes it easier for them because they knew what he wanted," said UNOS spokesman Anne Paschke. "They may say. 'My kid was very giving and so I think that's what he would have wanted.'"

As for the Greens, they understand the donor decision may be more difficult for some than others, especially when it involves a child.

"If you are put in a situation where it's your mother, brother, sister or husband, we don't think twice about [organ donation]," she said. "Certainly I understand it's a difficult decision and a personal choice and I don't want to judge people who don't want to do it."

When her mother died, Roxanna Green said the family discussed the possibility and even Christina was in on the decision.

"I understand it's a personal choice, but in our family, we are all about helping others and giving," she said.

Roxanna Green said that her daughter was not only passionate about helping others in the political realm -- the third-grader was on her school's student council -- but Christina-Taylor was interested in medicine as well.

"She wanted to be a vet or a doctor and so this was right down her alley," said her mother. "She would not think twice about helping animals that were hurt or friends that were hurt by visiting them. She was all about helping. This was not a hard decision at all for us to come to."

Roxanna Green said one day she might like to meet the donors who were saved by her daughter's organs.

"I don't want to invade on their privacy, but you know I would be happy to tell them it would be an honor for us," she said. "Our daughter is looking down from heaven, happy to give a small gift to help save someone's sight or help their life. She was a leader and a child older beyond her years. She is proud to do this."

"I am so sorry she is gone -- this is sad, violent and terrible," said Roxanna Green. "But we can learn from this and change."

The Greens are urging people to think ahead and prepare for a tragic moment when they might have to make the same decision.

"Learn from this," she said. "Do it now. Maybe you hadn't quite put it on your driver's license, but I am urging people to just do it now. Tell your loved ones you want to do it. Think in advance. A lot of people don't think about it until something really bad happens."

Roxanna Green said there "are no words" for the pain that she feels for the violent death of her daughter. "I can't describe it. It's a horrendous thing for anyone to have to go through at any age. It's especially hard to lose a child in such a horrible way."

But, she said, the family is working hard to move forward. "We are people of faith and we want to remain strong and try to get back with life and do what we are supposed to do."

Their son Dallas returned to elementary school today and his mother said, "He is doing better."

"His is doing well, considering," she said. "This is the first day he went back to school and we asked him over and over again, 'Are you really sure?' He wants to go back to school. He is a strong, strong person."

And she said the family has drawn strength from the outpouring of sympathy from so many other Americans.

'I have my faith, my family and friends and the nation has been amazing," said Roxanna Green. "I am so blessed and thankful for all the well wishes and want something good to come out of this. Be aware that this can happen to anybody at any time in any neighborhood, no matter how safe and cautious you are. But through all the sadness and bad things, in the organ donation process, there is happiness."